1. Field of the Invention
This invention broadly relates to an appliance that is secured to a tooth during the course of orthodontic treatment. More particularly, the present invention is directed to an orthodontic appliance having structure that facilitates manipulation, placement and removal of the appliance by the orthodontic practitioner.
2. Description of the Related Art
Orthodontia is a specialized field within the general subject area of dentistry. Orthodontic treatment involves movement of malpositioned teeth to correct locations along the dental arch. Orthodontic treatment can result in improved occlusion for the patient as well as a more pleasing aesthetic appearance.
One type of orthodontic treatment involves the use of a set of components that are collectively known as “braces”. In this type of treatment, small slotted devices known as brackets are secured to the patient's anterior, cuspid and bicuspid teeth. An archwire is received in the slots of the brackets and forms a track to guide movement of the teeth to desired positions.
Each end of an orthodontic archwire is often received in an enclosed elongated passageway of a small device known as buccal tube. Buccal tubes are connected to the patient's molar teeth. The enclosed passageway helps prevent the end of the archwire from contacting the patient's soft tissue in the oral cavity, which might otherwise lead to pain and injury. In some instances, buccal tubes are provided with a convertible cap along one side of the passageway that can be opened in order to convert the tube into a bracket when desired.
In the past, orthodontic brackets and buccal tubes were often welded to a metallic band that was adapted to encircle the patient's tooth. The band was selected to match the shape of the tooth in order to provide a secure connection between the tooth and the appliance. Typically, an adhesive known as band cement was placed along the inner circumference of the band in order to help avoid gaps between the band and the tooth surface. The cement also helped to preclude undue rocking of the band once the band was placed over the tooth.
Orthodontic bands are often manufactured with a shape that closely matches the expected shape of the patient's tooth. For example, the band may have one or more indentations that are adapted to be received between adjacent cusps of the molar tooth. Bands are usually not cylindrical but instead have somewhat flattened sides that are adapted to matingly fit against matching sides of a particular tooth.
When the practitioner places a selected band over the patient's tooth, the shape of the band (including any flattened regions and cusp indentations) helps to ensure that the band is properly positioned with respect to a rotative orientation about the longitudinal axis of the tooth. As a consequence, when the band is fully seated on the tooth, the band and the accompanying appliance are located in a proper, predefined orientation relative to the tooth. In many instances, the practitioner need only place the band in a rotative position that is approximate to the final desired position, since the band will often shift somewhat in rotative directions to accommodate the shape of the tooth as it slides across the tooth surface and moves toward its final desired position.
However, orthodontic bands are highly visible, especially when placed over the patient's front teeth that are near the mouth. Consequently, bands are not considered aesthetic. Bands can serve as a source of embarrassment to the patient, particularly among adolescent patients who may experience teasing from classmates. In addition, the steps of selecting the proper band and welding the selected band to the desired appliance result in an expense of time and money that is best avoided if at all possible.
As a result, there has been increased interest in recent years in the use of orthodontic appliances that are directly bonded to the surface of the tooth with an adhesive. Such appliances avoid the need for selecting a properly sized band and welding the appliance to the band at a certain, predefined location. Moreover, such appliances are considered more aesthetic in use because the lack of the band renders the appliance more difficult to see.
However, appliances that are directly bonded to the tooth surface, also are known as “direct bond” appliances, are generally considered to require careful attention by the practitioner when attempting to place the appliance to the tooth. According to certain types of treatment techniques, direct bond appliances should be positioned at certain, predefined locations on the tooth so that the tooth is properly oriented with respect to the remaining teeth at the conclusion of treatment. Placement of appliances at correct locations on the tooth is especially crucial when the practitioner is using the “Straight Edge” technique, a technique that aims to result in a straight and level archwire at the conclusion of treatment.
An orthodontic appliance that is improperly placed on the tooth surface may cause unsatisfactory treatment results. For example, if the appliance is bonded to the tooth at a location that is offset from its intended location, the resulting orientation of the tooth at the conclusion of treatment may be offset a corresponding distance if the practitioner is using the “Straight Edge” technique. As a consequence, precise manipulation of the appliance is often needed during the bonding procedure in order to ensure that the resulting placement of the appliance on the tooth is exactly as intended.
In addition, it is also important to ensure that the direct bond appliance is firmly embedded in adhesive during the bonding procedure. Conventionally, a layer of adhesive is placed on the base of the appliance and the appliance is then maneuvered into position over the tooth surface. The practitioner then presses the base of the appliance against the tooth, preferably with sufficient force to extrude a portion of the adhesive from the sides of the base. Such practice helps to ensure that there are no gaps or voids between the base of the appliance and the tooth, which might otherwise trap food and contribute to caries.
As such, manipulation of direct bond appliances during a bonding procedure is an important task, and mistakes are best avoided. Oftentimes, the practitioner will use a hand instrument such as fine-tipped pliers to hold the appliance and manipulate the appliance during the bonding procedure. However, orthodontic appliances are relatively small and visibility within the oral cavity is limited, especially in posterior regions next to the molar teeth. Maneuvering the appliance within the confines of the oral cavity is also troublesome.
Moreover, certain types of orthodontic adhesives exhibit characteristics that lend difficultly to the bonding procedure. For example, some types of orthodontic adhesives, known as “chemical cure” adhesives, begin a curing reaction as soon as two components of the adhesive are mixed together. Once the curing reaction begins, the practitioner must complete the bonding procedure before the adhesive has hardened. As a result, practitioners using chemical cure adhesives must work steadily and accurately to complete the bonding procedures within a certain period of time.
Although the orthodontic appliances that are currently available are considered generally satisfactory by many practitioners, there is a continuing need to improve the state of the art, particularly with respect to the placement and bonding of direct bond appliances. Preferably, such improvements would not only facilitate the practitioner's tasks but also help improve the results evidenced by the patient's dentition at the conclusion of treatment.